Aerodynamic air inlet for air-breathing propulsion systems

ABSTRACT

Means for effecting the induction of outside air into the combustion process of an air-breathing propulsion system such as ram jets, ducted rockets, and air-augmented rockets. A jet of fluid is exhausted at high velocity into the airstream just behind an open port in the skin of the vehicle. The injection of this fluid causes the formation of a shock wave some distance upstream of the point of injection. Air between this shock wave and the injection point is at a high pressure and thus flows into the open port in the skin of the vehicle. Thus, no external obstruction need be attached to the vehicle to divert air into the port.

United States Patent [72] Inventor Ronald F. Dettling China Lake, Calif.2| Appl. No. 31,099 [22] Filed Apr. 23, 1970 [45] Patented Nov. 30, 1971[73] Assignee The United States 01 America as represented by theSecretary of the Navy [54] AERODYNAMIC AIR INLET FOR AIR- BREATIIINGPROPULSION SYSTEMS 4 Claims, 2 Drawing Figs.

[52] US. Cl 137/815, 137/15.1, 244/53.8 [51] 1nt.Cl F1541 1/10 [50]Field oiSeareh 137/81.5, 15.1, 15.2; 244/53.8, 130

[5 6] References Cited UNITED STATES PATENTS 2,864,236 12/1958 Toure etal. 137/151 Primary Examiner-William R. Cline Anameys-R. S. Sciascia,Roy Miller and Gerald F. Baker ABSTRACT: Means for effecting theinduction of outside air into the combustion process of an air-breathingpropulsion system such as ram jets, ducted rockets, and air-augmentedrockets. A jet of fluid is exhausted at high velocity into the airstreamjust behind an open port in the skin of the vehicle. The injection ofthis fluid causes the formation of a shock wave some distance upstreamof the point of injection. Air between this shock wave and the injectionpoint is at a high pressure and thus flows into the open port in theskin of the vehicle. Thus, no external obstruction need be attached tothe vehicle to divert air into the port.

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FLOW FIELD WITH JET OFF FIG.

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INVENTOR. RONALD F DETTL/NG BY ROY MILLER ATTORNEY GERALD E BAKER AGENTAERODYNAMIC AIR INLET FOR AIR-BREATHING PROPULSION SYSTEMS BACKGROUND OFTHE INVENTION Air-breathing propulsion systems have heretofore requiredthat a physical scoop or other external obstruction be placed outsidethe body of the vehicle in the moving airstream so as to force a portionof the flowing air to be diverted to the interior of the propulsion unitwhere it may be mixed with a fuel and burned to yield propulsive power.Because this air must be slowed and turned by a physical obstructionattached to the vehicle a drag force opposite to the vehicle motion isproduced, requiring that the propulsion unit deliver additional energyin order to overcome this force. Such scoops or ducts also increased theoverall envelope of the vehicle adding to the aerodynamic problemsinvolving the shape and maneuverability of the vehicle.

According to the present invention, no external physical obstruction isused to induct the air. Instead, a jet of fluid is exhausted at highvelocity into the airstream just behind an open port in the skin of thevehicle. The injection of this fluid causes the formation of a shockwave some distance upstream of the point of injection. A high-pressurearea is thus created between the shock wave and the injection point tocause air to flow into the open port in the skin of the vehicle.

Various types of fluids, ranging from cold air to fluids which combustwith the outside air, may be used to form the shock wave and thehigh-pressure area from which air is inducted.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. I is adiagrammatic view of a section of the skin of a vehicle embodying theinvention; and

FIG. 2 is a view similar to FIG. 1 with changed conditions of fluidflow.

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, a vehicle hasa skin 12 formed with an open port intake passageway 14 leading to acombustor 20 which supplies motive power to the vehicle. During flightof the vehicle, air A flows in the direction of the arrows past the port14. A second port I6 is provided in skin 12 of the vehicle leading to afluid supply 18. Fluid may be expelled in a controlled manner by anyknown means. In the arrangement shown, it may be seen that there are noexternal obstructions jutting out from the surface 15 of skin 12.

Looking now at FIG. 2, as fluid is supplied from port 16, a fluid jet 13is formed jutting out from the surface 15 of a skin 12. Ejection of thefluid jet 13 causes, with the airflow A, a shock wave 17 which precedesthe frontal portion of the fluid jet and pressure buildup forces aportion of the air to flow into port 14 for use of combustor 20.

As stated above, various types of fluids may be used to form the shockwave to cause induction of air. A very strong shock wave withhigh-pressure area for very little mass of fluid can be had for examplewith fluids such as triethylaluminum or pentaborane which combustreadily with the outside air. In some instances, it might be considerednecessary or desirable to augment the effect by including a smallextensible and retractable flap but some reduction in efficiency must beexpected because of the air drag produced by such flap.

In the preferred embodiment, however, no external physical obstructionis used. Thus, the air drag on a physical obstruction is eliminated andthe propulsion system need not produce additional energy to overcomethis drag, resulting in an increase in propulsive efficiency. Also, by avariation in the amount and velocity of fluid exhausting from the shockproducing jet, a variation in the amount of airinducted into the openport is obtained, allowing efiicient operation of the ductssignificantly decreases the overall envelope of the vehicle, allowing itto be handled more easily and with less possi bility of damage tocritical parts of the propulsion system.

While the invention has been described in relation to a vehicle usingair for a motive power combustor, it will be appreciated by workers inother fields that the arrangement shown may be utilized in many otherapplications involving the flow of air along a surface and thedesirability of ingesting a portion of the air into a port in thesurface.

What is claimed is:

1. Means for ingesting air angularly into an elongated airframe bodyhaving relative motion with an air mass comprismg:

an intake passageway with said body communicating with said air mass andat an oblique angle near normal to the airflow around said body;

means including a second passageway for establishing a jet of fluid,spaced from said passageway rearwardly along the direction of relativemotion; such that, when a jet of fluid is so established, physicalinteraction of said fluid and said air mass causes air to be forced toenter said intake passageway.

2. Apparatus according to claim 1 wherein said fluid is highly reactivewith air thus increasing said physical interactron.

3. Apparatus according to claim 2 wherein said fluid is a liquidselected from the group consisting of;

triethylaluminum and pentaborane.

4. Apparatus according to claim 1 wherein said fluid is a liquidselected from the group consisting of; triethylaluminum and pentaborane.

i I I! III

1. Means for ingesting air angularly into an elongated airframe bodyhaving relative motion with an air mass comprising: an intake passagewaywith said body communicating with said air mass and at an oblique anglenear normal to the airflow around said body; means including a secondpassageway for establishing a jet of fluid, spaced from said passagewayrearwardly along the direction of relative motion; such that, when a jetof fluid is so established, physical interaction of said fluid and saidair mass causes air to be forced to enter said intake passageway. 2.Apparatus according to claim 1 wherein said fluid is highly reactivewith air thus increasing said physical interaction.
 3. Apparatusaccording to claim 2 wherein said fluid is a liquid selected from thegroup consisting of; triethylaluminum and pentaborane.
 4. Apparatusaccording to claim 1 wherein said fluid is a liquid selected from thegroup consisting of; triethylaluminum and pentaborane.